Norway's Karsten Warholm celebrates after running 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)

Norway's Karsten Warholm celebrates after running 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)

Norway's Karsten Warholm celebrates after running 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)

Norway's Karsten Warholm celebrates after running 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)

Norway's Karsten Warholm celebrates in front of the scoreboard after running 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)

Norway's Karsten Warholm, left, races to win in 46.70 seconds to set a new men's 400m hurdles world record at the Diamond League meeting in Oslo, Norway Thursday July 1, 2021. (Fredrik Hagen, NTB via AP)